Radiation induces cyclin B1 nuclear accumulation in a time-dependent manner.

(A) Ramos cells subjected to 400 cGy γ radiation and the indicated times after irradiation stained for cyclin B1 or cyclin D1 (green) or DNA (red). The overlay of the images is in yellow. (B) Ramos cells 4 hours after irradiation do not show evidence for apoptosis, as measured by annexin staining. (C) The irradiated Ramos cells have an intact nuclear membrane. Untreated cells or those 4 hours following irradiation were stained with antibodies specific for cyclin B1 (red) or lamins A/C (green). The nuclear lamin is intact in both treatments as evidenced by a circular lamin-staining ring (arrows). An overlay of the 2 colors indicates that cyclin B1 protein is within the nuclear lamina in irradiated Ramos cells. (D) Higher magnification of irradiated and unirradiated Ramos stained for cyclin B1 (red) or lamin A/C (green). Original magnification A,D, × 630.